Biomedical subjects

Constance Johnson

Publications and source records attributed to Constance Johnson.

4 recordsLinked to original sources

PubMed2004

Assessing informatics students' satisfaction with a web-based courseware system.

This study assessed health informatics student satisfaction with two subsequent versions of Prometheus, a web-based courseware system. Prometheus versions 4 and 5 were assessed to gauge the effect of modifications to improve the usability of the system. The Questionnaire for User Interaction Satisfaction (QUIS, version 7.0) was administered at the end of fall semester 2001 (in which Prometheus version 4 was used) and again at the end of Spring 2002 (in which Prometheus version 5 was used). QUIS contains measures of user satisfaction of the overall system and 11 specific dimensions, including screen, terminology and system information, learning, system capabilities, manuals and online help, multimedia, and teleconferencing. In general, students had favorable judgments of Prometheus, and their satisfaction level remained relatively stable across the two versions. However, usability enhancements incorporated into version 5 produced no significant differences in student satisfaction ratings. The results of this study provide a benchmark for comparing the relative usability of alternative courseware systems and demonstrate the utility of user satisfaction surveys for assessing and improving courseware systems. With increases in the need for compliance education and the education of clinicians with 'just in time knowledge', courseware systems will become an integral part of the clinical information systems, increasing the importance of usability studies such as this one.

Adult↗

PubMed2003

Multicolor in vitro translation.

In vitro translation is a widely used tool for both analytical and preparative purposes. For analytical purposes, small amounts of proteins are synthesized and visualized by detection of labeled amino acids incorporated during translation. The original strategy of incorporating radioactively labeled amino acids, such as [35S]methionine or [14C]leucine, has been superseded by the addition of antigenic tags or the incorporation of biotin-labeled or BODIPY-FL-labeled amino acids. Such nonradioactive tags are easier to visualize after translation and do not pose a radiation hazard. Among the nonradioactive tags, BODIPY-FL-lysine offers the advantage that proteins that have incorporated this amino acid can be directly visualized after gel electrophoresis. We show here that multiple fluorophores introduced into proteins can considerably extend their usefulness, particularly for the comparison of in vitro-translated proteins from related sources. This technology can be applied in various situations, including the simplified detection of rare truncating mutations in clinical samples from cancer patients.

Boron Compounds↗

PubMed2002

Detection of proximal colorectal cancers through analysis of faecal DNA.

Detection of mutations in faecal DNA represents a promising, non-invasive approach for detecting colorectal cancers in average-risk populations. One of the first practical applications of this technology involves the examination of microsatellite markers in sporadic cancers with mismatch-repair deficiencies. Since such cancers nearly always occur in the proximal colon, this test might be useful as an adjunct to sigmoidoscopy, which detects only distal colorectal lesions. We report here the first in-depth analysis of faecal DNA from patients with proximal cancers to determine the feasibility, sensitivity, and specificity of this approach. Using a sensitive method for microsatellite mutation detection, we found that 18 of 46 cancers had microsatellite alterations and that identical mutations could be identified in the faecal DNA of 17 of these 18 cases.

Adenoma↗

PubMed2002

Detection of APC mutations in fecal DNA from patients with colorectal tumors.

BACKGROUND: Noninvasive methods for detecting colorectal tumors have the potential to reduce morbidity and mortality from this disease. The mutations in the adenomatous polyposis coli (APC) gene that initiate colorectal tumors theoretically provide an optimal marker for detecting colorectal tumors. The purpose of our study was to determine the feasibility of detecting APC mutations in fecal DNA with the use of newly developed methods. METHODS: We purified DNA from routinely collected stool samples and screened for APC mutations with the use of a novel approach called digital protein truncation. Many different mutations could potentially be identified in a sensitive and specific manner with this technique. RESULTS: Stool samples from 28 patients with nonmetastatic colorectal cancers, 18 patients with adenomas that were at least 1 cm in diameter, and 28 control patients without neoplastic disease were studied. APC mutations were identified in 26 of the 46 patients with neoplasia (57 percent; 95 percent confidence interval, 41 to 71 percent) and in none of the 28 control patients (0 percent; 95 percent confidence interval, 0 to 12 percent; P<0.001). In the patients with positive tests, mutant APC genes made up 0.4 to 14.1 percent of all APC genes in the stool. CONCLUSIONS: APC mutations can be detected in fecal DNA from patients with relatively early colorectal tumors. This feasibility study suggests a new approach for the early detection of colorectal neoplasms.

Adenoma↗